Hex-PORTMAN: Heat Flux Splitting in Porous Materials for Thermal Management

Lead Research Organisation: Queen's University of Belfast
Department Name: Sch Mechanical and Aerospace Engineering

Abstract

Thermal management plays a vital role in determining the efficiency, safety and reliability of technological development in a plethora of industries including aerospace, automotive, computing and renewable energy sectors. The developments in these industries have culminated in a considerable surge in the power densities, which goes hand-in-hand with the increase of generated heat flux and subsequent undesirable temperature rise in system components. Porous materials (i.e. solids, which are permeated by a network of pores) have been demonstrated to be competitive microfluidic materials for effective cooling in high heat flux applications because of their fluid permeability and high surface area, which augments the heat transfer from hot surfaces to the cooling fluid passing through the porous media.

Past studies have theoretically investigated the flow and thermal characteristics of the porous media systems for thermal management using the volume-averaged approach, which is a popular low-cost engineering approach for studying transport in porous media. However, after more than a decade of research, this problem has still not been resolved. This is primarily because the splitting mechanism of the external heat flux between the solid and fluid phases in the porous media is unknown and determination of the thermal boundary condition for volume-averaged solvers remains a scientific challenge. This ambitious project will, for the first time, address this fundamental problem of flow and heat transfer in porous media systems through a comprehensive series of experimental and modelling studies.

This project will benefit from partnership with world-renowned scientists: Prof Kambiz Vafai (KV)-University of California Riverside, Dr Mahdi Azarpeyvand (MA)-University of Bristol and Prof Kamel Hooman (KH)-University of Queensland, with the involvement of one PDRA and four PhD students. KV is a world-leading scientist in the field of transport in porous media and will bring his key knowledge in understanding the heat flux splitting in the porous media. MA and KH will support the project for experimental measurements of the velocity field in the system. This project is also of direct relevance to industry with the involvement of UK-based companies (Glen Dimplex, B9 Energy, and BL Refrigeration) who will be deploying the fully validated volume-averaged solver developed in the project for the purpose of thermal management using porous materials in application to electronics cooling, energy storage and solar photovoltaic systems, respectively.

Planned Impact

Engagement with industry during and after this project will be the key to delivering economic impact and eventually getting products to market that will generate profit within the UK. The first project beneficiaries are the UK manufacturing sectors working in the field of thermal management in electronics for ground and space applications. In this sector, implementation of our low-cost modelling tool will allow heat exchange devices such as metal foam heat sinks to be designed more reliably. It has the potential to increase the cooling capacity of the electronic devices by 15% compared to the conventional finned heat sinks, which will increase the life-span of the devices and lower costs for end-users. This is clearly recognised by our industrial project partner, Glen Dimplex who will use the developed solver for their future design of thermal management devices for their electronics appliances. Additionally, the project has attracted the interests of UK-based manufactures in Clean Energy: (1) B9 Energy has recognised the project's benefit in manufacturing a novel liquid piston gas compressor (LPGC) for application to compressed energy storage system. As demonstrated in the letter by B9, deployment of the project's solver allows for an optimum design of a LPGC technology, which can have about 18% higher efficiency than the conventional LPGC system; (2) BL Refrigeration shows high interests in utilising the project's outcomes for an optimum design of cooling systems for Solar Photovoltaic (PV) panels. Such a cooling technology has the potential to increase the electricity production of PV panels by 10% over its 25 years life for a typical domestic household in the UK climate.

Societal impact will be realised by the application of the project's outcomes to large-scale applications in energy storage and solar energy. A recent study showed that by 2030, UK can meet emission reduction goals and electricity need predominantly using solar and energy storage along wind that can provide more than 60% of the total UK's electricity. Solar alone is estimated to create about 50,000 jobs per year, contributing £25.5 billion in GVA to the UK economy and putting £425 million back into consumers pockets. Thermal management using cost-effective materials such as metal foams have been specifically identified as technology drivers in solar PV and energy storage systems. This project will enhance our fundamental understanding of the thermal characteristics of flow in porous materials, which will contribute to this growing industry by improving the efficiency of the solar PVs and compressed air energy storage systems using metal foams. Additionally, the environmental impact of the project will be realised through supporting the UK's target in reducing GHG emissions by 80% by 2050, since instead of burning fossil fuels, solar PVs can be deployed for electricity production and compressed air energy storage for storing the surplus electricity for use on demand.

The additional benefits of the project to the general public will be through contributing to the training and education of UK engineers with the necessary skills in the area of experimental and computational fluid dynamics, which is an area of priority for EPSRC. The PI will directly benefit by expanding his research ambition, developing a strong international network, and strengthen his industrial and academic connections for future grant applications, which will lead to the future training of many more students and PDRAs. Pupils and students inspired by the research will seek careers in engineering. Clean and renewable energies are naturally inspiring to many students and the wider public. If successful, we envisage that the research findings will be incorporated into the undergraduate course at Queen's University, where each year, six final year students will benefit by spreading the project findings via interacting with the PI's current activities in supervising final year projects.

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